1. Field of the Invention
The present invention relates to a bicycle hub, and more particularly to a generator structure for a bicycle hub.
2. Description of the Prior Art
Most of the existing bicycle generators are disposed in the hub and generate power by utilizing the rotation of the bicycle wheels to cause the rotation of the rotor of the generator relative to the stator. However, the rotor and the stator for the existing generators are a permanent magnet and a yoke iron, respectively. The permanent magnets are currently all made of anisotropic bonded NdFeB, so that the permanent magnet can be made into a cylinder shape to generate power by cooperating with the yoke iron. The NdFeB-made cylinder-shaped permanent magnet can generate 3-12 MGoe of magnetic energy product by radial magnetization and orientation, and the generated voltage and power are both small. In order to generate relatively large power and voltage, the size of the cylinder-shaped permanent magnet must be increased, and the size of the bicycle hub for placement of the generator is consequently increased, thus increasing the weight of the bicycle while reducing the value of the bicycle.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages.